— But among investigated cases, 60% were ruled out

The number of confirmed microcephaly cases in Brazil is still rising, the country's health ministry said.

Some 4,783 suspected cases of microcephaly or other nervous system disorders had been reported by Jan. 30, the ministry said in a bulletin posted late Tuesday on its website.

Of those, 404 have been confirmed as involving microcephaly or other disorders of the nervous system, 709 have been ruled out, and the remaining 3,670 reports are still under investigation.

A link to the Zika virus was seen in 17 of the confirmed cases, the ministry said.

The bulletin added that there have been 76 reported stillbirths or miscarriages linked to microcephaly or other disorders of the nervous system. So far, 15 have been investigated and confirmed for microcephaly, including five with Zika virus found in fetal tissue, and five have been ruled out. The remaining 56 are still under investigation.

Meanwhile, the country's top health official said mandatory reporting of Zika infection will start next week, when most states will have labs able to detect the virus.

Health minister Marcelo Castro said the testing will help the country understand the extent of the epidemic, but he noted that most infected people will display no symptoms, according to the Reuters news agency.

The rapid spread of the virus itself is not a public health emergency, according to the head of an expert panel that recommended the call. It's "not a clinically serious infection," said David Heymann, MD, of the London School of Hygiene and Tropical Medicine in England.

Instead, the UN agency said the as-yet-unproven link between the virus and microcephaly is the emergency and the goal is to "get to the bottom of this," in the words of WHO director general Margaret Chan, MD.

It should facilitate "the necessary epidemiological and surveillance work," he told MedPage Today, but also improve prevention efforts, research into ways to prevent or treat Zika infection, and more consistent risk messaging.

On the other hand, Chan said, there is no justification for travel or trade restrictions and the WHO did not echo the travel advisories -- from the CDC and other agencies -- aimed at pregnant women.

And that was a mistake, according to Lawrence Gostin, JD, of Georgetown University's O'Neill Institute for National and Global Health Law.

The absence of a clear travel advisory puts the WHO "at odds" with the CDC, which urged pregnant women to avoid the regions where Zika is now circulating and to take precautions against being bitten by mosquitoes if they do travel there.

"The CDC also advised women considering becoming pregnant to talk with their doctor before traveling," Gostin noted in a statement. "That is the right thing to do from a public health and ethical perspective."

Duchin, though, told MedPage Today, that the WHO has to tread a "fine line" between communicating risks and overreacting.

A "counterproductive effect on trade" would hurt the ability of affected countries to battle the epidemic, he said.

The WHO did say that "attention should be given" to making sure that pregnant women and those of childbearing age know how to reduce risk of exposure to Zika and that pregnant women already exposed to Zika should be counselled and followed for birth outcomes.

The issue is complicated by the fact that the link between the virus and the cluster of microcephaly cases in Brazil remains unproven.

As the new numbers show, some of the reported cases involve clinical microcephaly but many do not. And lab-confirmed links to Zika infection remain rare.

Importantly, the baseline for how much microcephaly Brazil should see is unclear.

Practice parameters from the American Academy of Neurology and the Child Neurology Society suggest that the larger number is correct.

In contrast, before 2015 Brazil was reporting fewer than 200 cases of microcephaly annually with some 3 million live births a year. Investigators exploring the microcephaly cluster cautioned that the historical prevalence calculated from birth certificates -- about 0.5 cases per 10,000 live births -- was much lower than expected.

Accessibility Statement

At MedPage Today, we are committed to ensuring that individuals with disabilities can access all of the content offered by MedPage Today through our website and other properties. If you are having trouble accessing www.medpagetoday.com, MedPageToday's mobile apps, please email legal@ziffdavis.com for assistance. Please put "ADA Inquiry" in the subject line of your email.